Processor-based systems, including personal computers, servers, and mainframes, may include a number of features that impact the overall performance of the system. As described herein, performance includes characteristics such as the processing speed and the noise generated by the system (system noise).
The processing speed determines how quickly software running on the processor-based system is executed. The speed of the processor clock, the number and type of processors in the system, as well as the implementation of particular processing features, such as pipelining and caching operations, influence the processing speed.
The noise generated by the processor-based system, may result from the operation of drive media, such as fixed disk drives, floppy drives, compact disk read-only memory (CDROM) drives, and other non-volatile media, as well as by the operation of one or more fans contained within the system chassis. The fans, of which there may be several, may be used to cool the drive media, the processor, one or more power supplies, and/or the system board generally.
Sometimes, there exists an inverse correlation between processing speed and system noise within the processor-based system. This is because when the processor executes instructions at a higher clock rate, it tends to get hotter. Accordingly, a fan designated to keep the processor cool may operate at a faster speed (typically given in cubic feet per minute, or CFM) to maintain the processor at a safe operating temperature. The higher fan speed typically generates more noise. A higher performing processor may also draw more power, causing a power supply fan to deliver higher power and at a higher temperature, which may cause the power supply fan to run at a higher speed, thus increasing the noise level of the system. A program that requires frequent disk drive access may cause the drive to run at a higher average speed, which produces mechanical noise due to the spin of the drive. Thus, a system with a high-performing processor tends to be noisier than one with a low-performing processor, although this is not always the case.
Traditionally, users of processor-based systems have had little control over these performance characteristics. While some processor-based systems include a mechanism for changing the clock rate of the processor, these systems typically prevent the user from setting a clock rate that is faster than a manufacturer-recommended maximum clock rate. Industrious users have access to mechanisms to “over-clock” the processor, sometimes with a limited understanding about the effect such change may have on the life of the processor. Further, processor-based systems do not give the user the ability to control other performance-related characteristics, such as fan speed and disk media usage.
Thus, there is a continuing need for an apparatus that gives a user of a processor-based system some control over performance features.